Screen pipe with slots disposed in circular areas



Jan. 24, 1928.

J. H. M EVOY, JR

SCREEN PIPE WITH SLOTS DISPOSED IN CIRCULAR AREAS Filed May 19. 1926 1%2 JNT/ENTOR JOSEPH /7c 5/ Patented Jan. 24, 1928.

UNITED stares insane PATENT OFFICE.

Josnrn' nanny MQEVOY, :rnjor nousron, TE

SCREEN PIPE WITH SLOTS 31 Application filed May 19,

This invention relates to oil well equipment and it particularlyrelatesto a screen pipe adapted tloruse in an oil well. i

In the production of oiland gas from wellsit is common practice to usewhat is known as an oil string of pipe, this string extending downthrough the well casing into the oil bearing stratum. was for rnerly thepractice to drop the oil'sting in place in the oil bearing stratumand'then to perforate it from-the inside by means of a periorator, thispertorator producing; openings in the pipe through which the oil flowedinto theainterior of the well. the oil being removed from the welleither by means oi a pump or by natural flow. l Jhen the oil string wasso perforated the openings produced, whether inthe tornioit' round holesor slots, were unsatisfactory inasmuch as they could not be perforatedin small sizes, this resulting in the admittance oi": sand and gravel ofconsiderable site into the well which tended to interfere with theoperation thereof. It has, therefore, become standard practice toperforate the lower end. of the oil string before putting it in place inthe well and it has been found that it is desirable to perioratethe oilstring with thin elongated slots, these slots acting; as a screen andexcluding coarse sand and gravel from the Well. It has been found,however,

that if a suiiicient number of openings to freely admit oil is providedthe screen pipe, as it is denominated, is considerably weal:- ened, bothagainst longitudinal stresses and against forces tending to twistorcollapseit. I have found that by grouping the slots closer together thanin usual practice and confining; thorn into definite areas the capacityoi the screen pipe is not reduced, but the strength thereof iscmisiderably iiu creased.

it is accordingh an object of this intention to provide a screen pipe inwhich the slots therein are grouped together in definite confined areasfor the purpose of giving strength to the pipe. j

it is readily apparent that the greater the distance between thediil'erei'it groups or slots, the greater will be the strength of thepipe. I have found that by grouping the slots in confined circular areasthat greater distance may be provided between the different groups withbut a small sacrifice of capacity.

It is accordingly another object of this srosnn Lari crricunen Anna's.

1926. Seriai No/11037G.

inyention to provide a screen'pipe in which the slots thereinaregroupedin definite cir lustrate this invention p y c Fig. lis adiagrammatic view illustrating one utility of my invention.

2 is atragnientary plan View; showing clearly the inanner in which theslots screen pipe of my invention are located. Fig". 3 is a sectiontaken on the line 3+3 oi Fig. 2. y 5 is a fragmentary View illustratingthe spacing of the slots in tin-ordinary screen p ll .I. i i

in the drawings, 11 represents the tloor ot a derrick which is situatedover a well 12 which is provided with a string" of well casing; 13 whichextends down to apoint just above the oil be aring stratum i i. Thewater string or well casing 13 may be cemented, as shown at 17,to shutout surface water. Extending into the Well is a pipelS which is commonlytermed an oil string. L ,he lower end oft-he oil string 18 is providedwith a screen pipe 19 of my invention which extends through the oilbearing stratum 14', as illustrated in Fig. 1. Extending into the oilstring 18 is a puniptubing 21 which e1:-

tends through a casing head 22 connected to the upper end of the oilstring18 above the derrick floor 11. Near the lower end of the, well 12there is an oil well pump 23 which is connected to the lowerend fot thepump tubing 21 and by means of which oil is elevated to the surface ofthe grounds The screen pipe 19 which incorporates the tea tures of iny,invention is provided with. groups of slots 25 ,which are separated byimpertoratebridges 26. i

The" construction of the clearly illustrated in l i H groups of slotsiuclu elongated and narronwslcts27 which, as illustrated inFig; 3,1naybe keystone or wedge-shaped for the purpose of giving relief so thatthere will be but the reniotest tendency for them to clog. The slots 27of each group 25 (Fig. 2) are of different lengths. These slots 27 areso proportioned that they are situated inside a definite circular area.In other screen ,pip e 2 and ,3. The

Referring to the drawings in which I ilcular areas, a very wide bridge26 is formed between each group of slots. It should be noted that a muchwider bridge is provided by confining the slots in circular areas thanwould be possible if the slots were grouped in square areas. In Fig.2dotted lines 31 represent square areas. It will be seen that the samegrouping of slots in square areas would reduce the size of the bridgesvery greatly and a screen pipe having slots grouped in square areaswould lJB WGMKQI than the screen pipe of my invention hav ing the slotsgrouped in circular areas. is, of course, apparent that the capacity ofthe screen is reduced a little, since certain oi. the slots of eachgroup must be shorter than the longest slots of the group. It will beseen, however, that but very little ofthe screen capacity is sacrificedby shortening some of the slots of each group.

In Fig. 4; I illustrate a portion of the screen pipe having elongatedslots 36 formed therein. according to standard practice. These slots 36,as illustrated, are not confined to definite areas or arenot grouped;there are, therefore, no actual bridgesprovided between the-slots. Inthe ordinary screen pipe, as illustrated in Fig. 4, each slot is spaceda definite distance from the next slot, the slots throughout the entirelength of the screenpipe being of substantially the same spaclng.

In my invention I group the slots, placing the slots of each groupcloser together than the slots in anordinarycasing and-provideimperl'orate bridges 26 which are quite large and which give the screenpipe con siderable strength. Comparing Fig. 2 with Fig. l it will beseen that in the screen pipe of my invention 1 group seven slots into acoinparatirely small area as compared with the area occubiedby the sevenslots in the screen pipe shown in Fig. 4-. By placing more slots in agiven area, as illustrated by the comparison between Figs. 2 and 4-, Iam enabled to produce asereeu pipe having substantially the samecapacity as an ,ordi nary screen pipe, luit onewhich has inuch morestrength becauseof the ilnperforate bridges 26. d

It is quite important that the screen pipe have considerable strength towithstandany stresses which may be placed thereon. For

example, referring to Fig. l, the oilbearing stratum 14: is shown in aninclined extension, this being very common in such formations. When theoil bearing stratum is at an inclination there is more or less shiftingthereon. It the strainer pipe is not very strong and is unable to resistthe stresses imposed thereupon by the shifting formation,

it will undoubedly be collapsed. For this reason it is sometimespractice not to pro vide the ordinary form of strainer pipes with evenas many slots as shown in Fig, l. It will be quite evident that thescreen pipe of my invention will have much greater strength than theordinary screen pipelincause ofthe grouping of the slots to providebridgesQG and will, therefore, better resist the stresses imposedthereupon while in a well.

As previously explained the bridges 26 are made larger by grou 'iiug theslots in circular areas and this is an important part oi? the invention.Although my invention Ill has a particular utilityyin the oil producingindustry it should be understood that I may employ the idea in theconstruction of screens for other uses.

I claim as my invention:

1. A screen pipe having slots formed therein, said slots being paralleland grouped in confined areas so as to provide imperforate reinforcingbridges between each pair of adjacent groups, laterally disposed slotsof each group being shorter than slots centrally disposed, to cause eachgroup of slots to lit the boundaries of the area in which it isconfined.

2. A screen pipe having slots formed therein, said slots being paralleland grouped in confined areas so as to provide reinforcing bridgesbetween each pair of adjacent groups, laterally disposed slots of eachgroup being shorter than slots centrally disposed, to cause each groupof slots to lit the binindaries of the area in which it is confined.

3. A. screen pipe having slots formed in the material of the wallthereof, said slots being parallel and; grouped in confined areas cl asurface cl? said wall, the length of the slots of ear-h group decreasingprogres sively from the interior to theextcrior or each group. H

In testimony whereo t, I have hereunto set my hand at I-louston, Texas,this it) day of lilay, 1926. it

JOSEPH HENRY MclEVOY, JR,

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